EPIC 203868608: A Low-mass Quadruple Star System in the Upper Scorpius OB Association
Abstract
Young multiple star systems provide excellent testing grounds for theories of star formation and evolution. EPIC 203868608 was previously studied as a triple star system in the Upper Scorpius OB association, but the followup Keck NIRC2/HIRES/NIRSPAO observations reported here reveal its quadruple nature. We find that the system consists of a double-lined spectroscopic binary (SB2) Aab (M5+M5) and an eclipsing binary (EB) Bab with a total mass that is lower than that of the SB2. Furthermore, we measure the obliquity of the EB using the Doppler tomography technique during the primary eclipse. EPIC 203868608 Bab is likely on an inclined orbit with a projected obliquity of -57_(-36)^(+40) degrees. The inclined orbit is used to constrain the tidal quality factor for low-mass stars and the evolution of the quadruple system. The analytic framework to infer obliquity that has been developed in this paper can be applied to other EB systems as well as transiting planets.
Additional Information
© 2018. The American Astronomical Society. Received 2018 July 2; revised 2018 August 31; accepted 2018 September 2; published 2018 October 3. We thank the anonymous referee for his or her comments and suggestions that significantly improved the manuscript. We acknowledge Konstantin Batygin, Jim Fuller, and Fred Adams for discussions on tidal evolution and Kozai–Lidov perturbation in EPIC 203868608. We thank the PIs of KOA NIRC2 data, Christoph Baranec and Andrew Mann. S.A. acknowledges the support of the Danish Council for Independent Research, through DFF Sapere Aude Starting Grant No. 4181-00487B. Funding for the Stellar Astrophysics Centre is provided by The Danish National Research Foundation (Grant Agreement No. DNRF106). Part of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. T.J.D. acknowledges support from the JPL Exoplanetary Science Initiative. The data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Maunakea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain.Attached Files
Published - Wang_2018_ApJ_865_141.pdf
Accepted Version - 1809.01689.pdf
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Additional details
- Eprint ID
- 91954
- Resolver ID
- CaltechAUTHORS:20181221-105356785
- 4181-00487B
- Danish Council for Independent Research
- DNRF106
- Danish National Research Foundation
- NASA/JPL/Caltech
- W. M. Keck Foundation
- Created
-
2018-12-21Created from EPrint's datestamp field
- Updated
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2021-11-16Created from EPrint's last_modified field
- Caltech groups
- Astronomy Department